High voltage switch



Aug. 26, 1958 1.. c. HART HIGH VOLTAGE SWITCH Filed 00th 10. 1955 HHGHVQLTAGE SWITCH Lester C. Hart, Cicveland, Qhio, assignor to Joslyn Mfg.& Supply (30., Chicago, iii, a corporation of Illinois ApplicationOctober 10, 1955, Serial No. 539,367

Claims. (Cl. 200-146) The present invention relates to high voltageswitches, and, more particularly, to high voltage switches of the typeemployed in power distribution circuits, which, in addition to operatingas disconnecting or isolating switches for certain sections of the powerdistribution circuits, are also capable of interrupting substantialcurrents in the form of line charging currents, transformer magnetizingcurrents and even energy loads.

It Wiil be understood by those skilled in the art that high voltageswitches are extensively employed, particularly in outdoor switchingstations for isolating sections of transmission lines and the like undercertain conditions. Such high voltage switches are generally air breakswitches which are crank operated through a manual crank mechanism orthe like to isolate desired sections of the distribution circuits and toinsert other sections. it has been common practice to provide such highvoltage switches with arcing horns to interrupt transformer magnetizingcurrents and the like. However, as the distribution circuits have becomelarger and more complicated, the line charging currents have become solarge that such conventional air break switches have been incapable ofsatisfactorily interrupting the currents flowing. It would be desirableto provide a high voltage air break switch capable of switchingcapacitive currents such as those encountered in deenergizingtransmission lines, underground cables and capacitor banks. It wouldalso be desirable for such a high voltage switch to interrupt theenergizing current of large transformers. At the same time, such highvoltage or air break switch should conform in general to theconfiguration of the well-known high voltage air break switches soextensively employed for this purpose.

Various means have been suggested in connection with hi h voltage airbreak switches to provide some sort of current interrupting contacts inparallel with the current carrying contacts of the high voltage switch.Most of these arrangements have been very expensive, requiring acomplicated mechanism and many of them did not separate the arcingcontacts with sufficient velocity and did not provide sufiicient spacingto insure interruption.

Accordingly, it is an object of the present invention to provide a newand improved high voltage air break switch.

It is another object of the present invention to provide a new andimproved high voltage air break switch capable of interruptingcapacitive currents such as those encountered in deenergizingtransmission lines, underground cables and capacitor banks, and alsocapable of interrupting the energizing current of large transformers.

Still another object of the present invention is to provide a new andimproved high voltage air break switch comprising an attachment whichwill remain in contact while the main current carrying contacts of theswitch separate and then open with very high speed without oscillationor swinging back to at least partially reclose the *atent O It isanother object of the present invention to provide high velocityinterruption contacts in the form of an attachment for a high voltageair break switch readily applicable to existing high voltage switches.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize the invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

For a better understanding of the present invention, reference may behad to the accompanying drawing, in which:

Fig. 1 is an elevational view of a high voltage air break switchembodying the present invention showing several different positions ofthe switch during operation thereof;

Fig. 2 is a somewhat enlarged sectional view taken along line 22 of Fig.1;

Fig. 3 is a somewhat enlarged sectional View taken along line 33 of Fig.1;

Fig. 4 is an enlarged sectional view taken along line 4-4 of Fig. 1;

Fig. 5 is a fragmentary elevational view illustrating a modification ofthe present invention; and

ig. 6 is a sectional view taken along line 66 of Fig. 5. it will beunderstood that high voltage air break switches are generally employedfor multipole operation,

although they might equally well be employed for singlepole operation.To simplify the drawing, only a single pole of a high voltage switch hasbeen illustrated. However, it should be appreciated that in a multipoleswitch additional units identical to that shown in Fig. 1 of the drawingwould be provided with links interconnecting the operating mechanisms toinsure simultaneous operation of the switch blades.

In order to illustrate the present invention, there is disclosed in Fig.1 of the drawing a high voltage switch of the type shown in UnitedStates Letters Patent No. 2,514,263, Hart et al., granted July 4, 1950.This switch generally indicated at 10 may obviously comprise any form ofhigh voltage air break switch. As illustrated, the switch 10 comprises abase member 11 formed of channel iron or other suitable material whichwill provide a rigid member for supporting the switching contacts and operating means for air break switch 10. As illustrated, the base 11 isdisposed in a horizontal position. It should be understood, however,that it might equally well be disposed in a vertical or some otherposition, and the illustrated position is merely by way of example.Secured to the base 11 are a pair of fixed insulators 12 and 13 mountedin spaced relationship on the base 11. There is also provided a movableinsulator 14 positioned between the fixed insulators 12 and 13. Theinsulators 12 and 13 are provided with suitable means for securing themin a fixed position to the base 11. The insulator 14, on the other hand,includes a downwardly extending shaft 15 which is adapted for rotationin a suitable bearing 16 mounted on the base 11. As illustrated, the endof the shaft 15 disposed on the opposite side of the base 11 from theinsulator 14 is provided with a hexagonal end designated as 1511 whichmay be engaged by a suitable manual operating lever or the like to causerotation of the insulator 14. Preferably the bearing 16 and asubstantial portion of the shaft 15 are provided with a suitable sleethood 17.

For the purpose of operating the switch 10 as a multi pole switch, oneor more crank arms 18 may beprovided to rotate with the insulator andshaft 15. As illustrated, the crank arm 18 is provided with an operatingeye 19 which may be connected to suitable rods interrelating theplurality of poles of the multipole switch to insure simultaneousoperation of all poles thereof. It will be understood that in the eventa single-pole switch is desired, the crank arm 18 will be disposed with.Also, instead of employing a crank for engaging the hexagonal end of theshaft 15, it will be understood that power from a suitable source may beapplied to the crank arm 18 to operate the switch 10.

In order to support electrical conductors which together with the switch10 comprise the circuit to be controlled, there is mounted on theinsulator 12 a hinged base and terminal support 21. On the other hand,there is mounted on the insulator 13 a contact support 22. It will beunderstood that the supports 21 and 22 are suitably fastened to theirassociated insulators 12 and 13 in a conventional manner. Mounted on thesupport 22 is a stationary contact means or assembly generallydesignated at 23 and described in greater detail hereinafter. Thestationary contact itself is not visible in the drawing, since it iscovered by a sleet hood 24, preferably formed of bronze or the like. Itwill be understood that the stationary contact member may comprise anysuitable contact capable of carrying the currents at the high voltagesinvolved, and in general preferably comprises spring biased contact jawsfor engaging and receiving therebetween the bladelike contact portion 25of a switch blade 26. The support 22 also includes an extension 27 towhich a suitable terminal (not shown) may be bolted or otherwisesecured, which terminal is electrically connected to one side of thecircuit controlled by the switch 10. The support 22 further includes acontact base guide 28 for supporting and guiding the movable bladelikecontact portion 25 fastened to the end of the switch blade 26 in itsinitial movement during a circuit opening operation and its finalmovement during a circuit closing operation, when the switch blade movesendwise along its longitudinal axis.

Preferably and as indicated above, the switch 10 is of the type in whichthe switch blade 26 moves along its longitudinal axis both during theinitial opening movement and the final closing movement thereof, andduring the rest of its cycle of operation pivots or swings in an areabout the effective pivot point described hereinafter. To accomplishthis, the support 21, which is in the form of a casting suitably boltedor otherwise secured to the stationary insulator 12 has associatedtherewith a plurality of links 30, 31 and 32. The lower ends of thelinks 30 and 31 are pivoted to spaced points on the support 21, and theupper ends thereof are pivoted to spaced points on the link 32. The link32 is provided with an extension 32a connected to the switch blade 26. Asuitable crank 33 fastened to the rotatable insulator 14 is connected bymeans of a connecting rod, not visible in the drawing, with the link 32so that upon rotation of the insulator 14 the particular arrangement ofthe links 30, 31 and 32 causes the switch blade 26 to move substantiallyalong its longitudinal axis when in a position closely associated withstationary contact 23, and to pivot about an effective pivot pointremote from the end thereof supporting blade portion 25 for theremaining and major portion of the switch blade movement. Alsoassociated with the support 21 is a terminal extension 36 to which maybe bolted or otherwise secured to a suitable terminal (not shown)connected to the other side of the circuit to be controlled by theswitch 10. It will be apparent that the switch 10 provides a controlpath between suitable conductors connected to the terminal extensions 27and 36, respectively. As was pointed out above, the details of thestructure supported by the terminal supports 21 and 22 form no part ofthe present invention, but are fully disclosed and claimed in Hart etal. Patent No. 2,514,263 mentioned above.

By rotation of the insulator 14, assuming that the switch blade 26 is inthe closed position indicated in Fig. l of the drawing, it first movesalong its longitudinal axis in a direction toward the support 21 untilit is free of the stationary contact 23, and then it pivots about theeffective pivot point associated with support 21 to the successivepositions shown in dot-dashed and in dashed lines in Fig. l of thedrawing. When in the maximum open position, there is presented a verylarge air gap which is suificient completely to isolate the two sides ofthe high voltage circuit connected to terminals 27 and 36, respectively.

Before discussing the features of the present invention associated withthe high voltage switch described above, a brief discussion of theproblem of interrupting capacitive currents is believed to be desirable.When opening a capacitive circuit, there is always a moment of time whenconditions are perfect for circuit interruption. Perfect conditionswould, of course, comprise current zero and with no voltage across thecontacts at the instant of current zero. Actually, this occurs at thefirst current zero after the contacts of the switch have separated. Atthis moment when there is no current flowing, the voltage across thecontacts is also zero. This is because the voltage lags the currentabout ninety degrees and reaches its peak at current zero, but it shouldbe remembered that at this instant the condensers comprising thecapacitive circuit have been charged to a voltage equal to the peakvoltage, so that there is no diiference in the voltage across the switchcontacts to be opened. If, therefore, the interrupting contacts areseparated at a sufficiently high velocity at the instant of current zerowhen no voltage drop occurs across the contacts so as to provide duringthe next half-cycle after the first current zero a sufficiently wide gapwhich will not break down, the circuit will remain interrupted. Forinterrupting the energizing currents of large transformers, initiallyhigh speed separation of the contacts is also essential and this highspeed separation must continue through a distance almost equal to thenormal open gap of the switch. The present invention satisfactorilyinterrupts capacitive currents and transformer energizing currents.

Referring now to Figs. 1 to 4 of the drawing, the high velocityinterrupting contacts of the present invention, connected in parallelwith the switch blade 26 and stationary contact 23, essentially comprisea resilient rod or whiplike member 40 preferably formed of stainlesssteel and ground to a taper so as to gradually taper from one end to theother. Moreover, the stainless steel rod or whip 40 is preferably heattreated so as to be very resilient. In accordance with the presentinvention, the large end of the tapered rod 40 is suitably secured orclamped to the pivotal end of the blade 26 in a manner so as normally tobe disposed in spaced parallel relationship with the blade 26, as isclearly shown in the solid lines and in the dashed lines of Fig. 1 ofthe drawing. As best shown in Fig. 4, a suitable rod support 41 isprovided of somewhat L-shaped configuration. The rod 40 is suitablysecured, preferably as being inserted within a sleevelike portion 41a ofthe support 41. This support is clamped as by clamp means 42 to theblade 26 closely adjacent the end thereof, which rotates about theeffective pivot described above. In this manner the resilient taperedrod 40 is supported in cantilever fashion with respect to the blade 26,the free end of the rod 40 extending beyond the blade portion 25, as isclearly apparent from Fig. l of the drawing. The whiplike rod 40 iseffectively the movable interrupting contact of the high velocitycircuit interrupting contacts paralleling the current carrying contacts26 and 23.

T 0 provide a cooperating interrupting contact, there is supported onthe support 22 and electrically connected therewith a catch 44, bestshown in Fig. 2 of the drawing. This catch 44 comprises the stationaryinterrupting contact and is illustrated as having a sort ofarrowheadshaped projection 44a, which defines on either side thereofshoulders 45 and 46 which are adapted to engage the free end of theflexible rod 40. In Fig. 2 of the drawing the rod 40 is indicated ascooperating with the shoulder 46, but it might equally well cooperatewith the shoulder 45. The arrowhead shape of the portion 44a will guidethe rod 40 during the closing movement of the air break switch to moveinto engagement with either shoulder 45 or 46. The combined stationarycontact and switch latch or catch 44 further includes projections 44band 44c disposed beneath the shoulders 45 and 46, respectively, whichfunction to guide the resilient tapered rod 40 and insure ultimateengagement thereof with one of the shoulders 45 or 46. Moreover, thearrangement is such that whenever the switch blade 26 is moved to theclosed or solid line position of Fig. l of the drawing, the free end ofthe rod 40 moves into engagement with one or the other of the shoulders45 or 46 of the catch 44. During the opening movement of the switchblade 26 it will be apparent that as it pivots from the solid lineposition to the dot-dashed line position of Fig. 1, the free end of therod 40 will remain in engagement with the catch 44, and due to itsresilience, it will assume the bowed position shown in dot-dashed linesin Fig. l. The length of the rod 4% is sufficient so that it remains inengagement with the catch 44 until the blade contact portion 25 of theswitch blade 26 has separated from the associated stationary currentcarrying contact 23 to such an extent that a gap which will not restrikeis provided when the whiplike member 49 is suddenly released from thecatch 44. Continued movement of the switch blade 26 toward the dashedline position will cause the free end of the whiplike member 4h to bereleased from the catch 44 and whip at high speed in a manner tointerrupt the circuit at the arcing contacts and eventually come to restrelative to the blade 26 in the position shown in dashed lines in Fig. 1of the drawing. Actually, the fully open position of switch It? is notshown in the drawing.

The arrangement described above, without more, would result inoscillation of the whiplike member 41 during the switch openingoperation with the possibility of restriking of the are when the member4d moves to ward the catch or stationary arcing contact 44 duringoscillation thereof. To insure dependable interrupting operation, thereis provided a dampering mechanism generally designated by the referencenumeral 48 and best shown in Fig. 3 of the drawing. This damperingmechanism is disposed so as to be engaged by the whiplike member 40during the circuit opening operation so as to quickly bring it to restwithout oscillation which would cause restriking of the arc to beinterrupted thereby. As illustrated, the dampering mechanism 48comprises a support member 49 clamped as by clamping screws St} to theend of the blade 26 adjacent the blade contact portion 25. The support49 includes a projection 4% to which is secured a resilient member 53preferably in the form of a fiat stainless steel leaf spring. The spring51 is illustrated as being mounted so as to be disposed generallyparallel with the blade 26 and the whiplilze rod 48 when the latter isin its at rest position. Secured to the free end of the leaf spring 51is a flat spring 52 disposed in the form of a loop and preferably alsoformed of a strip of stainless steel bent into the form of a resilientloop and secured in any suitable manner to the leaf spring 51. The loopis of sufficient width, as is clearly shown in Fig. 3 of the drawing, sothat the whiplike rod member Ml will strike it, whereupon the kineticenergy in the whiplike member 4% may quickly be absorbed therebypreventing any undesirable oscillations of the rod -40.

Preferably the support 49 also includes a guide portion 4912 whichdefines with the portion 49a a sort of V-shaped guide to receive thereinthe whiplike rod member 40. The dampering mechanism 48 has been found towork very satisfactorily and insures high velocity interruption of theare so that satisfactory interruption of capacitive currents andtransformer energizing currents can be accomplished. It will, moreover,be appreciated that the high velocity contacts can be applied as anattachment to existing switches in a very simple manner by merelysupplying the dampering mechanism 48, the catch 44 and the rod member 40with its mounting means. The mechanism for interrupting high voltagecurrents is very sturdy and many years of satisfactory operation areinsured.

if it should be desired to afford still higher relative separationbetween the interrupting contacts, a modification of the presentinvention as illustrated in Figs. 5 and 6 of the drawing may beemployed. This modification consists solely in a modification of thecatch 44. The corresponding parts of Figs. 5 and 6 are designated by thesame reference numerals as in the preceding embodiment. As illustratedin Figs. 5 and 6 of the drawing, there is provided a spring catch 54formed of resilient spring wire material. As illustrated, the catch 54comprises a wirelike member which is formed to provide a sort ofarrowhead-shaped portion 54a defining the shoulders 55 and 56corresponding with the shoulders 45 and 46 described above. Theintermediate portion of the catch 44- comprises a turn or two designatedas 541) acting some what like a coil spring. It will be appreciated thatthe catch 54 has a portion which will tend to follow to some extentduring the switch opening operation the whiplike contact 40 as shown inother than solid lines in Fig. 5

. of the drawing. Consequently, upon separation of the whiplike rodmember 40 from the resilient spring catch 54, both the spring catch 54and the rodlike member 40 will tend to move in opposite directions, thusinsuring even higher speed contact separation than in the arrangementdisclosed in Fig. 1 wherein the catch 44 is stationary. Additionally, alonger gap is also produced in a shorter space of time, thus insuringoperation within the halfcycle period most satisfactory for interruptinghigh voltage capacitive currents and transformer energizing currents.The catch 54, although somewhat movable, may still be characterized asthe stationary interrupting contact, cooperating with the movableinterrupting Whiplike rod contact 40.

it will be appreciated that although the present invention isparticularly adaptable for high voltage air break switches whethermounted for horizontal or vertical operation, the invention is alsoapplicable to other types of switches such as hook operateddisconnecting switches and the like.

In view of the detailed description included above, the operation of thehigh voltage switch of the present invention will readily be understoodby those skilled in the art and no further discussion thereof isincluded herein. It will be apparent that there has been provided asimple arrangement for converting high voltage air break switches tosuch switches capable of interrupting high line charging currents,transformer magnetizing currents and the like. The means for convertingsuch conventional air break switches to switches capable of interruptingcapacitive circuits and the like is very simple and inexpensive, andresults in a switch which will give long years of satisfactory service.

While there have been shown and described particular embodiments of thepresent invention, it is not desired that the invention be limited tothe constructions shown and described, for it will, of course, beobvious to those skilled in the art that numerous changes andmodifications can be made without departing from the invention in itsbroader aspects. It is, therefore, intended in the appended claims tocover all such changes and modifications as fall within the true spiritand scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. A high voltage switch comprising a pair of relatively movable currentcarrying contacts, one of said current carrying contacts being supportedon a movable elongated switch blade, a pair of relatively movable arcinterrupting contacts connected in parallel with said current carryingcontacts, one of said are interrupting contacts including an elongatedresilient whiplike rod contact normally disposed in spaced parallelrelationship with said elongated switch blade and supported for movementtherewith, said rod contact being at least coextensive With said switchblade, the other of said are interrupting contacts comprising a latch,said latch holding said whiplike rod contact in electrical engagementduring a substantial portion of the switch opening operation, means forabsorbing the kinetic energy of motion of said rod contact when releasedby said latch comprising a loop of resilient material, and means forsupporting said loop from the said blade in a position to be struck bysaid rod contact when released by said latch.

2. The switch of claim 1 wherein the last mentioned means comprises aresilient member disposed parallel with said switch blade.

3. The switch of claim 1 wherein said loop comprises ill a fiat strip ofstainless steel supported from one of said current carrying contacts.

4. The switch of claim 1 wherein said rod contact is tapered.

5. The switch of claim 1 wherein said rod contact is formed of stainlesssteel.

References Cited in the file of this patent UNITED STATES PATENTS1,702,075 Chireix et al Feb. 12, 1929 1,825,002 Kratzer Sept. 29, 19311,861,641 Nicholson et a1 June 7, 1932 1,919,065 Jacobs July 18, 19332,317,118 Schultz et a1. Apr. 20, 1943 2,572,625 Johnson Oct. 23, 19512,727,105

Turner Dec. 13, 1955

